Method of manufacturing a sealed contact

ABSTRACT

A method for closely controlling the tolerances involved in the manufacture of a contact assembly is accomplished by a predeterminately positioned oblong hole in one corner of both the base plate and cover, and a predeterminately positioned circular hole in another corner of both the base plate and cover. Placement of the base plate and cover upon respectively positioned circular and oblong pegs allows the contact members of both the cover and base plate to exactly align. Welding of the base plate and cover is thereby accomplished within very close tolerances. The holes remaining in the finished contact are useful for aligning and mounting the contact during later operation.

United States Patent Biittel METHOD OF MANUFACTURING A SEALED CONTACT Inventor: l-lelmut Biittel, Leonberg-Eltingen,

Germany Assignee: International Standard Electric Corp., New York, NY.

Filed: Nov. 12, 1973 Appl. No.: 415,029

Foreign Application Priority Data Dec. 1, 1972 2258968 Germany US. Cl. 29/630 B, 29/622, 29/630 R Int. Cl H01r 9/00 Field of Search 200/245, 252, 257, 275, 200/284, 293; 29/630 R, 630 B, 622, 593; 335/154, 133,135, 136

[ Feb. 11, 1975 Martin 29/630 B Nordin 29/630 B [57] ABSTRACT A method for closely controlling the tolerances involved in the manufacture of a contact assembly is accomplished by a predeterminately positioned oblong hole in one corner of both the base plate and cover, and a predeterminately positioned circular hole in another corner of both the base plate and cover. Placement of the base plate and cover upon respectively positioned circular and oblong pegs allows the contact members of both the cover and base plate to exactly align. Welding of the base plate and cover is thereby accomplished within very close tolerances. The holes remaining in the finished contact are useful for aligning and mounting the contact during later operation.

5 Claims, 4 Drawing Figures PAIENIED 1 I975 74. 864,826

sum 1 OF 2 Fig.2

METHOD OF MANUFACTURING A SEALED CONTACT BACKGROUND OF THE INVENTION The present invention relates to a method of manufacturing a sealed contact with a flat housing consisting of a plane base plate with a glass-to-metal seal and a hood-shaped cover, which cover is provided with an armature designed as a flat component fastened to the cover with the aid of an armature holding spring. This contact is described in detail in a copending application by W. Mecklenburg et al Ser. No. 417,984 entitled Magnetically Actuated Sealed Contact, assigned to the assignee of the present invention.

The manufacture of sealed contacts depends to a large extent on the type of material that the contact housing is made of. For this reason welding as well as soldering can be used when joining two flat housing parts to form a contact.

The individual parts forming a contact, when seriesmanufactured in great quantities, tend to have large variations in tolerance which are likely to accumulate and to have a considerable influence upon the quality of the finished contacts. One of the measures for keeping the tolerances of the individual parts during assembly as small as possible, has so far not yet been taken into account in the conventional methods of manufacturing or assembling the contact.

The contacts involved within the scope of this invention are quite small, and some of the components within the contact are miniature. When, for example, the diameter of the electrical contact area within the relay is in the order of millimeters, the manufacturing tolerances must be held to a minimum to avoid misalignment problems.

The electrical contacts within the contact assembly consist of a pair of contacts, one on the cover portion of the assembly, and one on the base. Electrical continuity through the assembly is accomplished by means of magnetically attracting the electrical contact of the cover into contact with the electrical contact on the base. If the electrical contacts do not contact each other in nearly exact correspondence in contact area serious problems could occur resulting in eventual failure due to the electrical contacts becoming stuck in a closed position. The placement of the electrical contact on the cover, and the placement of the electrical contact on the base involve a great deal of precision so that when the cover and base are eventually sealed together, their corresponding electrical contacts will perfectly align. This amount of precision is costly in both equipment and time, since close tolerances must be kept for assembling the electrical contacts both to the cover and base, and also for sealing the cover to the base.

This invention, therefore, is based on the problem of providing a method of manufacturing a sealed contact so that the contact members within the housing, as well as the two parts of the housing itself, will be positioned opposite each other with as little displacement as possible.

SUMMARY OF THE INVENTION According to the invention the adding or accumulation of the tolerances of the individual parts during the assembly to form the finished contact, is largely avoided by providing for an exact positioning of the individual parts in relation to certain fixed points.

Accordingly, since little attention will have to be paid to the displacement ofthe contacts, it is possible to employ essentially smaller contact members, thus causing the product to become more inexpensive.

The individual parts during manufacture, therefore, do not need such narrow tolerance control providing a cost reduction for the entire contact.

Since the oppositely arranged contact members are of a rectangular design and oppose each other crossways in the finished contact. it is an additional advantage that there is always provided large overlapping of the contact-making surfaces.

According to the invention there is provided a method for closely controlling the tolerances involved in the manufacture of a contact assembly. This is accomplished by a predeterminately positioned oblong hole in one corner of both the base plate and cover, and a predeterminately positioned circular hole in another corner of both the base plate and cover. Placement of the base plate and cover upon respectively positioned circular and oblong pegs allows the contact members of both the cover and base plate to exactly align. Welding of the base plate and cover is thereby accomplished within very close tolerances. The holes remaining in the finished contact are useful for aligning and mounting the contact during later operation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top view enlarged drawing showing the cover 1, the armature 5 and the armature spring 6;

FIG. 2 is a top view of the base plate 7' showing the location of the outer part 2, the inner part 3 and the glass ring 4;

FIG. 3 shows a finished contact in a top view of the top side of the cover 1 on an enlarged scale; and

FIG. 4 shows a finished contact as in FIG. 3 incross section.

DESCRIPTION OF THE PREFERRED EMBODIMENT As described in FIG. 1, the cover 1 is of a hoodshaped design and is provided in its interior with an annular shoulder 14. Within this annular shoulder 14 a magnetizable armature 5 designed as a flat component, is retained in position and fastened by means of an electrically conducting armature holding spring 6. The spring is welded to the inside of the cover 1, e.g., at the points 21 and 22.

The armature holding spring 6 is designed as a stretched flat spring of rectangular cross section, and has a fiat position of rest. The armature holding spring 6 is divided into three fingers by means of two parallelextending incisions (notches, cuts) 7 and 8. To the two outer ones of these fingers 9 and 10, for example at the points 23 and 24, there is welded the armature 5 while to the free end of the middle finger 11 there is attached a contact member 12.

The contact member 12 as attached to the finger of the contact spring 11 has a rectangular design and is in such a way mounted to the contact spring 11 that the longitudinal direction of the contact member 12 extends in parallel with or vertically in relation to the iongitudinal direction of the contact spring 11. The armature 5 is provided with a recess 25 into which the contact member 12 as fastened to the contact spring 11 is permitted to project.

The cover 1 is rounded off on one side following the shape of the shoulder 14, whereas the external dimensions of the cover 1 on the other side, by following the lines 27 and 28, end up in two rounded-off corners I and 16 which are again joined by the line 29. In the resulting corner there is a bore 17, and in the corner 16 there is arranged an oblong hole 18.

The base plate 1 as shown in FIG. 2 consists of an outer part 2 and of a disc-shaped inner part 3 which are joined together by means of a glass ring 4 as to be flush in one plane on the inside of the base plate 1'. The outer shape of the base plate 1' consists of a semi-circle 26' which, at a certain spacing, extends in parallel with the outer diameter of the glass ring 4 and, at the sides, extends into the lines 27' and 28' ending up in the rounded-off corners l5 and 16. The corners l5 and 16' are joined by the line 29'. In the corner 15' there is arranged a bore 17, and in the corner 16 there is provided an oblong hole 18'. On the disc-shaped inner part 3 there is arranged a rectangular contact member 13 in such a way that either the longer or the shorter side of the contact member 13, in dependence upon the position of the contact member 12, will extend in parallel with the line 29.

The holes 17 and 17' as well as the oblong holes 18 and 18' are used advantageously per cover or base plate unit when manufacturing the units according to FIGS. 1 and 2 described hereinbefore.

Since the armature holding spring 6 is already welded to the armature 5 at the points 23 and 24, and the contact 12 is arranged in a predetermined position in relation to the contact spring 11, at a correspondingly spaced relation to the inner wall of the recess 25 in the armature 5, the unit consisting of the armature 5 and of the armature holding spring 6 is now available as a semi-finished article.

When this unit consisting of the armature 5 and of the armature holding spring 6, prior to the welding inside the cover 1, is brought into the proper position, then the receiving holes 17 and 18 in the corners 15 and 16 of the cover I will provide the exact positioning of the cover so that the contact 12 within the circular shoulder 14 of the cover I, will assume its proper position without any considerable deviation. In this exact position welding of the armature holding spring 6 to the cover 1 may be carried out within the shoulder 14.

Conditions are similar in the case of the basic unit described with reference to FIG. 2. The base plate 1' consisting of an outer part 2 and of a disc-shaped inner part 3 which are firmly joined to one another by means of a glass ring 4, is already available as a pre-fabricated part.

In order to be able to attach the contact member 13 without any considerable deviations, to the intended point on the disc-shaped inner part 3, once more the receiving holes 17' and 18 as provided for in the corners 15' and 16 are utilized. In this way it is assured that the contact member 13, within close tolerance, is attached to the proper position on the disc-shaped inner part 3, and in the proper position with respect to the outer edge line 29'.

As is further evident from FIG. 3 it is proposed for 6 the final assembly of the contact, hence for assembling the contact between the cover I and the base plate I, that the cover I and the base plate I are placed in such a way on top of each other .that the two inner parts of both the cover 1 and the base plate 1 will correspond. In so doing, and by means of pins correspondingly arranged in the, device (not shown), and extending through the holes 17 and 18 of the cover, and through the holes 17' and 18 of the base plate 1', these two basic units are aligned in a proper position relative to one another. This alignment assures that the two contact members 12 and 13 will come to lie exactly op- I posite each other with only a minimum deviation.

Following the alignment of the cover I in relation to the base plate 1, these two units are tightly welded along the annular shoulder 14. The welding along the annular shoulder 14 may be carried out in the conventional way either with or without being previously treated with a protective gas in a chamber filled with a protective gas or without a'chamber merely by being supplied with protective gas.

At the sealed contact shown in FIG. 3 on the cover side there is a depression 19 having a concave downward direction which, as shown more clearly in FIG. 4, serves to adjust the armature 5 to adjust the spacing between thp' contact members 12 and 13 respectively.

As likewise shown in FIG. 4, an indentation 20 is pro- 'vided on the under side of the armature 5. Both of the impressions l9 and 20, however, are not subject to the present invention, and have been described herein only for the sake of completeness.

The receiving holes 17, 18, 17' and 18 therefore provide a method for manufacturing a contact with very close tolerances, and also provide holes useful for mounting and fastening the finished contact.

While I have described above the principles of my invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of my invention as set forth in the objects thereof and in the accompanying claims;

I claim:

I. A method of providing a'sealed contact for use in an electromagnetic relay said contact having a flat base plate assembly containing a glass-to-metal seal, an electrical contact, a hood-shaped cover assembly including an armature fastened to the cover by means of an armature holding spring, the method comprising the following steps:"

a. forming a pair of first holes of predetermined shape and location in said base plate assembly;

b. forming a pair of second holes of predetermined shape and location in said cover assembly;

c. positioning said base plate assembly by fitting said first holes over a first set of pegs in registry with said first holes;

d. positioning said cover assembly upon said base plate by fitting said second holes over a second set of pegs in registry with said second holes;

e. sealing said cover assembly to said base plate assembly while said cover and said base plate assemblies are held in position by means of their respective pegs;

f. removing the contact from said pegs; and

g. mounting and aligning said contact in said relay by means of said first and second pairs of holes.

2. A method of manufacturing a sealed contact according to claim 1 wherein the step of forming said first holes includes forming a pair of holes having first and second shapes and being predeterminately located.

3. A method of manufacturing a sealed contact according to claim 2 wherein said first shaped hole is circular and said second shaped hole is non-circular.

4. A method of providing a sealed contact for use as an electromagnetic relay comprising the following steps:

a. forming a pair of first holes of a predetermined shape and location in a base plate for a sealed contact;

b. forming a pair of second holes of a predetermined shape and location in a cover assembly for said sealed contact;

0. positioning said base plate by fitting said first holes over a first set of pegs in registry with said first holes;

d. securing a contact member to said base plate while said base plate is positioned by said first holes and pegs;

e. positioning said cover assembly over said base plate by fitting said second holes in said cover assembly over a second set of pegs in registry with said second holes; I

f. sealing said cover assembly to said base plate while said cover assembly and said base plate are held in position by their respective said first and second pegs and holes;

g. removing the contact from said pegs; and

h. mounting and aligning said contact in said relay by means of said first and second pairs of holes.

5. The method of manufacturing a sealed contact according to claim 4 including the step of introducing a protective gas atmosphere prior to sealing said cover assembly to said base plate. 

1. A method of providing a sealed contact for use in an electromagnetic relay said contact having a flat base plate assembly containing a glass-to-metal seal, an electrical contact, a hood-shaped cover assembly including an armature fastened to the cover by means of an armature holding spring, the method comprising the following steps: a. forming a pair of first holes of predetermined shape and location in said base plate assembly; b. forming a pair of second holes of predetermined shape and location in said cover assembly; c. positioning said base plate assembly by fitting said first holes over a first set of pegs in registry with said first holes; d. positioning said cover assembly upon said base plate by fitting said second holes over a second set of pegs in registry with said second holes; e. sealing said cover assembly to said base plate assembly while said cover and said base plate assemblies are held in position by means of their respective pegs; f. removing the contact from said pegs; and g. mounting and aligning said contact in said relay by means of said first and second pairs of holes.
 2. A method of manufacturing a sealed contact according to claim 1 wherein the step of forming said first holes includes forming a pair of holes having first and second shapes and being predeterminately located.
 3. A method of manufacturing a sealed contact according to claim 2 wherein said first shaped hole is circular and said second shaped hole is non-circular.
 4. A method of providing a sealed contact for use as an electromagnetic relay comprising the following steps: a. forming a pair of first holes of a predetermined shape and location in a base plate for a sealed contact; b. forming a pair of second holes of a predetermined shape and location in a cover assembly for said sealed contact; c. positioning said base plate by fitting said first holes over a first set of pegs in registry with said first holes; d. securing a contact member to said base plate while said base plate is positioned by said first holes and pegs; e. positioning said cover assembly over said base plate by fitting said second holes in said cover assembly over a second set of pegs in registry with said second holes; f. sealing said cover assembly to said base plate while said cover assembly and said base plate are held in position by their respective said first and second pegs and holes; g. removing the contact from said pegs; and h. mounting and aligning said contact in said relay by means of said first and second pairs of holes.
 5. The method of manufacturing a sealed contact according to claim 4 including the step of introducing a protective gas atmosphere priOr to sealing said cover assembly to said base plate. 